What is the best AWD system?

thedguy

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See I'm the opposite. I prefer the front end as the give way point and having total confidence in the rear.
The first (and so far only) time I've understeered in a car un-intentionally I was sliding toward a granite wall trying to exit a turn. Since I had exceeded the adhesion point on my front tires I had 0 steering and my brakes were severely reduced (as fronts tend to do most of it). I had this feeling that I wasn't going to be able to stop in soon enough and adding to that no ability to change direction and I got panic'd.

On the other hand when the ass end comes loose on my miata, I just turn my hands a couple of degrees in the direction I want to go and hold the throttle. Hell that car is so controllable I can actually hit the brakes and still save it.
 

TBoneUs

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The first (and so far only) time I've understeered in a car un-intentionally I was sliding toward a granite wall trying to exit a turn. Since I had exceeded the adhesion point on my front tires I had 0 steering and my brakes were severely reduced (as fronts tend to do most of it). I had this feeling that I wasn't going to be able to stop in soon enough and adding to that no ability to change direction and I got panic'd.

On the other hand when the ass end comes loose on my miata, I just turn my hands a couple of degrees in the direction I want to go and hold the throttle. Hell that car is so controllable I can actually hit the brakes and still save it.
This man speaks truth. Identical circumstances, identical wall if you substitute granite for limestone. Terminal understeer is much much more terrifying in my opinion.
 

Necx0

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:lol::lol::lol: You don't drive fast... ever, do you?
Entering my 4th year of competition in hillclimb, circuit, autocross and state class rally champion last year. Nup never drive fast:D

This has given me problems in adapting to front wheel drive on gravel as its very important to get the tail out on entry but getting there.
 

LeVeL

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ok, fair enough, I retract my previous statement. That begs a question though... Why in the world do you prefer understeer?!?!??!
 

Necx0

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Ok this could get quite rambling but I will try to keep it on task. Simply put for me its easier to make an understeering car oversteer than an oversteering car understeer. I only mean when I am trying to go fast, when I am having fun there is nothing better than having the tail swinging everywhere.

Its all about confidence for me, it may be that setting the car up to be lively in the rear may be faster but lets say I am approaching a corner. If I have the front end as the give way point I brake as hard as the front tyres allow just to the point of lock up, if the rear end was the give way point I would have to worry about locking the rears and making steering corrections, not what I want when trying to find the last couple of meters in braking.

Now I enter the corner. Again with the front end as the give way point I feel the tyres load up and gently start to slide. As long as you have roughly guessed the correct entry speed the understeer won't be a major issue. If the rear is the give way point I turn in and all is good at the front so I apply more lock or carry more speed but then the rear gives way and I have to catch the resulting slide meaning 1. I drift away from my ideal line and 2. I am unable to get on the throttle (in a rwd car)

On exit understeer can be an issue if you apply too much throttle too soon or carried too much speed to the apex but if you judged those previous things correctly then you are on a good line and can now open your steering angle thereby constantly lessening the stress on the front tyres while feeding more throttle in with the confidence that wheelspin won't be too much of an issue due to strong rear grip.

This is mainly my thought process when driving rwd cars. On gravel in my fwd rally car its different as I should be sideways into the corner and straight driving out. Trouble is with such a short wheelbase it tends to go sideways very very quickly and both times I crashed it this year I went off backwards after carrying too much speed in to a corner. I drove the rally car at a streaming wet circuit though and power understeer is just about the shittest thing there is. Have to treat the throttle like an eggshell because as soon as it starts wheelspinning the front just washes wide.

I am not saying this is right or it IS actually the fastest way but its how I like to drive. Its also how Walter Rohrl and Sebastien Loeb drive and they are pretty good role models to have.
 

JipJopJones

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I understand what you mean, (I think) but from what I'm getting it only applies to FWD cars.

In a RWD car, if you understeer, (in FWD too, unless in one of your circumstances) you have lost all your control. You cannot accelerate, it will push wide. You cannot turn, your understeering. You can't really brake that well either. Atleast when the tail comes out in a RWD I still have control of (most) of my braking and steering.

Just my take on it. Correct me if you see a fault.
 

MadCat360

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I understand what you mean, (I think) but from what I'm getting it only applies to FWD cars.

In a RWD car, if you understeer, (in FWD too, unless in one of your circumstances) you have lost all your control. You cannot accelerate, it will push wide. You cannot turn, your understeering. You can't really brake that well either. Atleast when the tail comes out in a RWD I still have control of (most) of my braking and steering.

Just my take on it. Correct me if you see a fault.
Sure you still have control. The difference between the understeer that Nec is describing and what you're describing is simply the initiation. Nec is probably driving his car like a racing driver, in other words, he's using the tractive capability of the car and is exceeding the tractive limit of the tires as a whole to get his understeer. Most normal drivers, and novice racing drivers, will generally feel understeer as a result of doing something that makes the front end lose it completely and totally without ever being near (relatively) the capabilities of the car, ie, early apex, early throttle, etc. This has to do with weight transfer primarily as well as other things.

Managing terminal understeer (fronts way over the limit, rears still in total passive mode, no slip angle, going to hit the wall) is just as much about anticipation as wheel spin oversteer is. The only solution is to brake. And I guarantee you have more braking force available to you than you think or what your feet tell you. A car's collective contact patch is not round, it's egg shaped. You can always use braking and throttle to exceed the car's theoretical g force limit. Say .9G sideways (maximum cornering force), maybe another .3 or .4 G forward under trail brake. I can take a Miata around an autocross course constantly playing the limit of the ABS engagement and get a really fast time. At low speeds, in a car like that, you can use maybe 80% braking pressure while cornering without locking the tires, even at the limit of sideways traction. At that speed, you need to use that much braking force to get the car to rotate into the corner.

The other thing you have to worry about with terminal understeer is what some charismatic people call "pushy-loose", which is where you have the understeer, you have a lot of lock on, you maybe lift the throttle or adjust brake pressure or pass the apex and suddenly the tires bite and the rears swing wide.

But most terminal understeer maladies can be solved by either altering line or trail braking more, usually braking more. Most people just pootle through a corner without any brake, feel the understeer in the entry and think they're at the limit. If you use the brake in the corner, you'll slowly but surely progress to a point where you can actually use the entire tractive capability of the car as a whole rather than just driving how the (front) tires tell you. This is a huge false limit. Rotation allows higher rolling speed, and allows better angle at the apex, so you can come off the corner much faster as well as get to the apex faster.

That's my interpretation of what my coaches tell me.

EDIT: Personally, I prefer and understeery car for going fast against the clock or other people, and most racing drivers of this day and age do as well. There's still people (generally with sensetive right feet and not big on trail braking) who prefer a loose car, but I don't. Sliding scrubs speed, understeer doesn't unless it's terminal (you shouldn't be racing) or just a really bad setup not utilizing the car (fire your engineer).

That said if I was buying a fun car, I don't want understeer.
 
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Necx0

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MadCat has pretty much hit it on the head as I would have expected given his experience. Another point is you can make an understeering car oversteer. Stab of throttle in a rwd (although that could of course make your understeer worse) or a pull of the handbrake. I simply cannot see how you would make an oversteering car understeer. All about options.

I like to brake to within a few km/h of my ideal apex speed then allow the scrub of the front tyres to peel off those last few km/h while I turn in. See Fernando Alonso circa 2005-6 for an extreme example of this technique.
 

LeVeL

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Trailbraking is done to eliminate understeer, which means that if you trailbrake you are trying to get rid of the understeer. It gets the tail out a bit and tucks the nose in.
 

TBoneUs

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Just wanted to qualify my previous statement. I was referring to which was more scary. I prefer my AutoX setup to be slightly more stable, as I gain much more time through stability in the slaloms and sweepers than I would with a very loose care in the tight turns.
 

MadCat360

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Trailbraking is done to eliminate understeer, which means that if you trailbrake you are trying to get rid of the understeer. It gets the tail out a bit and tucks the nose in.
That's part of it, but the biggest thing about trail braking is to exceed the normal (untalented?) angle of attack at the apex and to utilize the rear tires to give you more cornering traction. If you turn in after releasing brake pressure, the front tires will turn, initiate to their slip angle limit based on the speed and radius of the corner, and then the rear tires will just sit there twidddling their thumbs. You need to use the brake to get the rears to do work on the entry. That has a side-effect of eliminating understeer in a properly set up car.

Rubbing the brake to kill understeer is just the same as holding off the throttle on the exit in a FWD car. Too many people don't treat the brake as a second steering wheel, like they do with the throttle.
 
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MadCat360

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^Keep talking guys I am SO taking notes :glasses:
lol, 2 years of racing school plus the combined doctrine of 9 paid professional coaches; 100,000 dollar value, yours free on the Final Gear forums!

Nec and I could start a seminar tour. :lol:

Seriously though, the only reason I (and I only speak for myself) know any of this is because I was so butterfingered when I started that I had to study my behind off just to become competitive. Nec definitely has seniority of experience over me. I don't even have my own race car at this point! Maybe next year.

Anyway, I'm struggling to think of more on understeer... I think we basically covered it.

EDIT: In terms of actually handling a FWD or AWD biased to the front, generally working to the strengths of the car's handling will make you faster. For instance, since a FWD car will understeer really bad on the throttle if it's got a simple diff, you'll want a later apex and more rotation at the apex. If you take a normal RWD line in a FWD car and slowly doll out the power to counter throttle-on understeer, you won't be utilizing the car's full accelerative capability. Certainly you still need to use "string theory" (string tied from wheel to gas, gas goes on, wheel goes off evenly and at same rate) and feed your gas on at the exit, but if you can rotate the car enough at the apex, and take a late enough apex to use the full capability of the front tires on exit, then even though you're accelerating later, you'll probably be at a higher MPH at track out. That's good just as long as you didn't sacrifice too much MPH for that later apex/turn in. MPH on the straights is good, but you should always be thinking in time, since that's what the scoring computer thinks in.

What I would do is take a normal RWD line for the first lap(s), then slowly extend my apex until it costs me time to the next corner, assuming it's not a "combo corner". As soon as it starts costing me time, I'd ratchet it back one notch to a slightly earlier apex and I'd probably be in really nice shape.

Nec can probably comment a lot better on FWD handling as that's the car he races.
 
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